Creating　an　efficient　method　that　can　provide　simple,　practical　and　high-throughput　separation　of　oil–water　mixtures　has　proved　extremely　challenging.　Two-dimensional　layered　Ti3C2Tx　MXene　material　with　excellent　hydrophilicity　has　attracted　substantial　attention　for　oil–water　separation.　However,　conventional　Ti3C2Tx　separation　membranes　are　susceptible　to　contamination　by　oil　due　to　its　relatively　high　adhesion　to　oil,　hindering　its　practical　applications　in　high-efficiency　oil–water　separation.　To　make　Ti3C2Tx　have　underwater　superoleophobicity　and　low　oil　adhesion,　the　surface　of　Ti3C2Tx　can　be　modified　by　introducing　hydrophilic　groups.　Herein,　L-lysine　functionalized　Ti3C2Tx　(Ti3C2Tx-Ly)　was　firstly　prepared　by　decorating　L-lysine　on　Ti3C2Tx　through　electrostatic　interaction　and　hydrogen　bonding.　A　facile　dip-coating　method　is　then　used　to　coat　polyurethane　(PU)　sponge　with　Ti3C2Tx-Ly,　obtaining　a　superhydrophilic/underwater　superoleophobic　Ti3C2Tx-Ly　@PU　sponge.　Owing　to　the　excellent　underwater　superoleophobicity　resulting　from　hydrophilic　groups　(–OH–NH3)　on　the　surface　of　Ti3C2Tx-Ly　nanosheets　and　the　enlarged　interlayer　spacing　of　Ti3C2Tx,　the　Ti3C2Tx-Ly　@PU　sponges　demonstrated　outstanding　separation　performance　for　a　series　of　oil–water　mixtures.　Specifically,　the　Ti3C2Tx-Ly　@PU　sponge　exhibits　low　oil　adhesion　and　superhydrophilic　(WCA　=　0°)/submerged　superoleophobic　(UOCA　＞　155°)　properties.　The　Ti3C2Tx-Ly　@PU　sponges　displayed　the　best　separation　performance　for　cyclohexane/water　mixture,　and　the　maximum　permeation　flux　is　up　to　221892　L　m–2　h–1,　accompanied　by　a　remarkable　separation　efficiency　of　higher　than　99.2%　after　100　cycles.　The　permeation　flux　has　exceeded　most　of　the　previous　reported　multifunctional　separation　membranes.　In　addition,　the　Ti3C2Tx-Ly　@PU　sponge　also　showed　excellent　separation　performance　for　high-density　oil　dichloromethane/water　with　a　separation　efficiency　over　99.4%.　Of　note,　the　Ti3C2Tx-Ly　@PU　sponge　features　excellent　chemical　stability　to　corrosive　media,　such　as　acidic,　alkaline,　and　high　salt　solutions,　possessing　great　potential　for　real-world　applications.　Furthermore,　the　as-prepared　Ti3C2Tx-Ly　@PU　sponge　exhibits　rapid　and　efficient　separation　of　oil-water　mixtures　through　a　fully　gravity-driven　process,　which　makes　it　a　good　candidate　for　industrial　oil-contaminated　water　treatment　and　oil　spill　clean-up,　and　also　provides　new　insights　into　the　design　and　development　of　functional　Ti3C2Tx　through　L-lysine　modification.　Therefore,　this　work　reports　a　facile　and　promising　way　to　fabricate　scalable　superhydrophilic/underwater　superoleophobic　sponge　material　for　highly　efficient　oil–water　separation.　©　2022　Elsevier　B.V.